1. Field of the Invention
The present invention relates to a communication control device, a communication control method, a program and a communication system.
2. Description of the Related Art
Communication means by which a high communication speed can be obtained are available for general users today, like the proliferation of the 3rd generation cellular phone terminals. Accordingly, massive contents such as music, games or videos are widely distributed on cellular phone networks. A communication scheme used for cellular phone networks would continue to become more and more sophisticated, and the amount of data transmitted and received on cellular phone networks is projected to increase continuously. Further, installation of additional base stations and expansion of a communication service area are expected in order that users can use cellular phone terminals without restraint, even indoors where radio waves are difficult to reach, for example.
Meanwhile, high-speed broadband lines such as FTTH, ADSL or CATV are also widespread in ordinary households, and connection services that can be used with no time restriction at a flat rate, for example, are widely used. In view of such circumstances, introduction of an indoor small base station that enables a connection from a cellular phone terminal to a high-speed broadband line indoors, for example, is being studied. Advantages of introduction of indoor small base stations for cellular phone carriers are that a service area of cellular phones can be expanded to the indoors where radio waves are difficult to reach, a communication speed is expected to improve compared to the outdoors where radio resources are shared by a plurality of users, costs are low compared to installing additional outdoor base stations and so on. Further, cellular phone users can expect reduction of communication expenses as a result that the above merits for carriers are given to the users in addition to improvement of a communication speed at home.
However, in the case where an indoor small base station is additionally installed in an existing cellular phone service area established by a plurality of macro base stations, interference among radio channels is assumed to occur between an indoor small base station and an outdoor macro base station, between a user of an indoor small base station and a user of a macro base station, between a plurality of indoor small base stations and so on. This can adversely affect the quality of the existing cellular phone service. In order to avoid such an issue of interference, it is necessary for an indoor small base station to grasp the usage status of radio channels of nearby base stations and set a parameter such as a frequency of a radio channel or a transmitting power so as to avoid interference. Further, assuming that indoor small base stations will be popularized step by step in a metropolitan area where residences, office buildings and so on are densely packed, the above-described interference avoidance process should be performed dynamically. In light of this, Japanese Domestic Re-Publication No. 2006-54341, for example, proposes a technique of making inquiries about location information of nearby base stations and the setting status of radio channels to a server installed on a carrier network at the start or restart of an indoor small base station and setting a radio channel of the indoor small base station based on the acquired information.